1. Field of the Invention
The present invention relates to a fluid suction nozzle adapted to form a local space surrounded by an air curtain and also to a fluid-treating apparatus adapted to clean, condition, or otherwise treat the air inside the local space.
2. Description of the Related Art
The present applicant has already filed Japanese Patent Application Serial No. 169893/1990 for "Fluid Suction Nozzle and Fluid-Treating Apparatus". Such an apparatus is shown in FIG. 8, wherein a suction nozzle, indicated by numeral 1, is connected with an air cleaner 3 via a duct 2. The nozzle 1 comprises an inner member 4 and an outer member 5 that is slightly spaced from the inner member 4.
When a fan 6 incorporated in the air cleaner 3 is driven, the air discharged from the fan passes through an outer passage 7 formed inside the duct 2. The air then passes through an annular discharge passage 8 formed between the inner member 4 and the outer member 5 of the nozzle 1, and is forced obliquely downwardly into a room 9. A local space 10 is surrounded by this air flow, indicated by AC. The air occupying the space 19 is drawn into a suction passage 11 formed inside the inner member 4 of the nozzle 1. Then, the air passes through an inner fluid passage 12 formed int he duct 2 and enters the air cleaner 3, where the air flows downwardly through a filter 13, dust collecting material 14, and a deodorant 15. In this process, the air is cleaned. The air is again drawn into the fan 6. Subsequently, the process described thus far is repeated.
In the above-described apparatus, the ratio .psi. of the flow rate of air Q.sub.S drawn into the suction passage 11 to the flow rate of air Q.sub.D discharged from the discharge passage 8 is set greater than 1, i.e., .psi.=Q.sub.S /Q.sub.D is greater than 1. Therefore, contaminated air around the air flow AC is caught in the air flow AC and enters the local space 10. This has set a limit on the cleaning of the air occupying the local space 10.